A study of subcellular distribution of cadmium within animal lung cells after toxic inhalation exposure will be undertaken. Special emphasis will be placed on characterizing the molecular structure(s) surrounding the metal. The relationship between cadium and the interacting macromolecule(s) will be investigated in order to understand the mechanism of toxicity (mechanism of action) of the metal. Electron paramagnetic resonance (EPR), nuclear magnetic resonance (NMR), and other spectroscopic techniques will be used to probe the immediate environment around cadmium. The subcellular distribution pattern of cadmium in normal lungs and those subjected to chronic inhalation exposures of cadmium oxide has been established in these laboratories. The cumulative data demonstrates a shift of cadmium, normally associated with the connective tissue and cell membranes of the lung, into the cell cytoplasm. Further effort will be expended to separate and to categorize the molecular components to which cadmium is bound. Established purification procedures such as gel filtration chromatography and electrophoresis will be employed to obtain electrophoretically and ultracentrifugally homogenous components, anticipated as being primarily low molecular weight molecules. The specific absorption attributes to metallothionein(s) at 250 millimicrons, characteristic of cadmium mercaptide bonds, will be used as monitor for isolation of that component when present. A comparison between the binding of cadmium to molecular constituents of the lung and kidney will be made.